Introduction: The anterior transpetrosal approach (ATPA) is a commonly used for managing lesions in the posterior fossa (PF). This study proposes a variation of the transorbital endoscopic approach (TOEA) that uses the lateral orbit as the primary surgical corridor as an alternative approach for an anterior petrosectomy as to the PF.
Methods: Anatomic dissections were carried out in five latex-injected human cadaveric heads (10 sides). During dissection, TOEAs for anterior petrosectomy to reach the PF, were carried out first, both with and without lateral orbital rim osteotomies; herein referred as, the lateral transorbital approach (LTOA) and the lateral orbital wall approach (LOWA), respectively. ATPAs were performed following the TOEAs. For each approach, stereotactic measurements of the area of exposure, surgical freedom, and angles of attack to five anatomical targets, were obtained for statistical comparison.
Results: LTOA provided the smallest area of exposure (1.51 ± 0.5 cm2, p = 0.07), while the exposures produced by LOWA and ATPA were similar (1.99 ± 0.7 cm2 and 2.01 ± 1.0 cm2, respectively; p = 0.99). The degree of surgical freedom was the largest for ATPA, while that of LTOA was the most restricted. Similarly, for all targets, the vertical and horizontal angles of attack offered by ATPA were significantly wider than those afforded by LTOA. In contrast, after the removal of the lateral orbital rim, the horizontal angles in LOWA improved significantly, making them comparable to those yielded by ATPA for three of the five targets.
Conclusions: Obtaining access to PF by using the lateral transorbital corridor, is a novel and feasible technique that provides adequate surgical exposure. Furthermore, the removal of the orbital rim significantly enhances the surgical maneuverability to anatomical targets in the PF.
Patient Care: This study will provide extra knowledge of the advantages and limitations offered by these novel minimally invasive techniques.
Learning Objectives: 1. To highlight the advantages of modern minimally invasive neurosurgical techniques.
2. To describe the surgical nuances of the transorbital endoscopic approach to the posterior fossa.
3. To quantitively analyze and compare the surgical exposures and degrees of maneuverability provided by each approach.